JPH05212621A - Wire cut electric discharge machine - Google Patents

Abstract

PURPOSE:To provide a wire cut electric discharge machine capable of precise working by measuring a pre-working shape precisely with high speed in no contact therewith for reworking on the basis of the measured value. CONSTITUTION:In a wire cut electric discharge machine which moves a wire electrode and workpiece relative to each other along a desired shape programmed by a numerical control device to cut the shape by the electric discharging machining, a shape measuring devices 1-11 for detecting a reflected beam in the irradiation of a laser beam by a beam position detector 5 and utilizing the principle of triangulation to measure the shape are provided. A preworking shape provided by wire cut is measured by the shape measuring devices 1-11 and the measured values are inputted to the numerical value control device to correct the programmed shape for reworking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire cut electric discharge machine.

[0002]

2. Description of the Related Art When a shape is cut by electric discharge machining while performing relative movement between a wire electrode and a workpiece along a desired contour shape programmed by a numerical controller, an electric discharge pressure or liquid is applied to the wire electrode. Pressure and gas pressure act to cause vibration and bending. Therefore, it is not always possible to precisely machine the programmed shape by numerical control, and it is unavoidable that a certain degree of error occurs in the machined shape. Usually, the bending of the wire electrode is about 30 to 50 μm, and it is difficult to keep the processing accuracy below that.
In particular, when machining a curved surface portion or a corner portion that changes the direction of the machining path, the machining accuracy is significantly reduced. For this reason, conventionally, a method of changing the depth of cut of a shape that has been machined once and reprocessing by changing the machining pulse conditions, feed rate, etc. has been adopted, but the setting of the depth of cut is not always optimal. There is a drawback that you do not go. In this case, in setting the depth of cut, it is conceivable to measure the size, shape, etc. of the preceding machining groove width and set a predetermined value based on it, but the measurement control can always be easily and precisely performed. is not. In the contact measurement, the measurement speed cannot be increased, and since the measurement pressure is applied, the pressurization causes a measurement error. In particular, it is extremely difficult to measure the curved surface shape.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to measure a previously machined shape in a non-contact manner with high precision and at high speed. An object of the present invention is to provide a wire-cut electric discharge machining device capable of performing precise machining by correcting the program shape of the numerical control device based on the value and remachining.

[0004]

To achieve the above object, the present invention provides relative movement between a wire electrode and a workpiece along a desired shape programmed by a numerical controller. In a wire cut electric discharge machine that cuts a shape by electric discharge machining, a shape measuring device that detects reflected light when a laser beam is irradiated by an optical position detector and performs shape measurement using the principle of triangulation, is provided.
It is characterized in that the pre-machined shape by wire cutting is measured by the shape measuring apparatus, the measured value is input to the numerical control apparatus, and the program shape is corrected and re-machined. In addition, a liquid removal device is provided that ejects gas from the nozzle toward the processing part and removes the processing liquid in the processing part.
It is recommended that the liquid removing device is operated to remove the working liquid in the working portion when the pre-processing shape by wire cutting is measured by the shape measuring device.

[0005]

As described above, the present invention is provided with the shape measuring device which detects the reflected light when the laser beam is irradiated by the optical position detector and measures the shape by utilizing the principle of triangulation. Pre-processed shape by cutting can be measured with high accuracy and high speed without contact. Also, by scanning the laser spot, it is possible to easily measure arbitrary shapes, curved surface shapes, etc., and it is easy to digitize the measurement results. This measurement value can be input to the numerical controller to correct the program shape. The process can be performed very easily.
Then, by performing rework finishing of the wire cut by this correction program, extremely high precision shape cutting can be performed. Further, at the time of measurement by the shape measuring device, a liquid removing device for ejecting gas from the nozzle toward the processing portion to remove the processing liquid is provided, and the processing shape is measured while removing the processing liquid, thereby performing a precise measurement and High-speed measurement can be performed very easily, and highly efficient and highly accurate wire-cut electric discharge machining can be performed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings. FIG. 1 is a principle diagram of a shape measuring apparatus that detects a displacement of a light spot of reflected light by an optical position detector such as a PSD or a CCD and measures the shape by a triangulation method. 1 in the figure
Is a laser semiconductor, 2 is a reflection mirror for changing the direction of the laser beam, 3 is a condenser lens, 4 is a lens for receiving reflected light on an axis forming a predetermined angle from the irradiation beam axis from the condenser lens 5, P for detecting the light receiving spot of reflected light
An optical position detecting element such as SD or CCD, 6 is an amplifier for amplifying both ends output of the optical position detecting element 5, and both outputs are switched and output by a switch 7 operated by a timing pulse. 8
Is an arithmetic processing unit for A / D converting the output signal of the amplifier 7, performing linear correction by three CPUs, further performing data processing such as averaging, and displaying and outputting the measurement result. Reference numeral 9 is a timing pulse oscillator, which is the switch 7,
The timing pulse is supplied to the CPU and the like, and the timing pulse is also supplied to the vibration pulse power source 10. Reference numeral 11 is a coil for controlling the vibration of the reflection mirror 2 and is a pulse power supply for vibration.
It is excited at a predetermined pulse frequency by the timing pulse current from 10.

Reference numeral 12 is a workpiece to be wire-cut electric discharge machined, and 12a is a machined groove which has already been machined. The shape of this machined groove portion is measured. That is, when the light beam emitted from the lens 3 hits the surface of the workpiece 12 and is reflected,
Among the reflected waves, the reflected light of the light receiving axis at an angle different from the light projecting axis is condensed by the light receiving lens 4, and the light spot is detected by the light position detecting element 5. Since the movement amount y of the light spot on the light position detecting element 5 changes according to the displacement x of the reflection surface of the workpiece, the principle of the triangulation method is to detect this y and measure the displacement x. .. An arithmetic processing unit 8 converts a change in an electric signal caused by a movement of a light spot on the optical position detection element 5 into a digital signal, and outputs a measurement result by performing data processing such as linear correction and average processing. You can

Then, the right-angled reflection mirror 2 forming the light projection system is vibration-controlled by the vibration coil 11, and the light beam irradiated from the lens 3 to the workpiece 12 is reciprocally scanned. By swinging the scanning direction in the width direction of the wire-cut machining groove, a difference occurs in the reflected light between the surface of the workpiece 12 and the groove 12a, and while repeating this vibration scanning, along the machining groove (direction perpendicular to the paper surface). The shape of the machined groove 12a can be measured with high accuracy and high speed by detecting and measuring while moving.

A semiconductor laser having a normal wavelength of 670 nm is used as a light beam, and measurement can be performed with a high resolution of about 0.2 μm. The measurement result is input to an NC controller for wire-cut feed control to correct the program. Done,
By reworking, extremely high precision wire cutting can be realized.

FIG. 2 shows an embodiment of a wire-cut electric discharge machining apparatus according to the present invention, in which a work piece 12 is fixed on a table 13 which is driven and controlled in X and Y axes, and an X axis motor 14 and a Y axis motor 15 are provided. Is controlled by the NC controller 16 to give a predetermined machining feed. Reference numeral 17 is a fine wire wire electrode having a wire diameter of about 0.05 to 0.3 mmφ, which is supplied from a reel and moves between upper and lower guides 18 and 18 sandwiching a workpiece with a predetermined tension and speed. 20 is a wire electrode 17 and a work piece 12 via an energizing pin 21.
A power supply connection terminal for supplying a machining voltage pulse between them.
Reference numeral 19 is a machining fluid supply nozzle for ejecting machining fluid from upper and lower guide portions, 22 is a measuring head incorporating the shape measuring apparatus shown in FIG. 1, and an air jet nozzle 23 is provided at the tip of the light guide portion. .. Reference numeral 24 is a drive motor for adjusting the vertical position of the measuring head 22.

In the wire cutting, an X-axis, Y-axis motor 14, a Y-axis motor 14, a workpiece 12 is pre-programmed by an NC controller 16 with respect to a wire electrode 17 which moves vertically.
By driving 15 to move the workpiece 12 side, a machining feed is given, and by supplying a machining voltage pulse from the power supply connection terminal 20 between them, pulse discharge is repeated to perform electric discharge machining. Upper and lower machining fluid supply nozzles 19, 19 during electrical discharge machining
In order to perform stable machining, the machining liquid is cooled by jetting the machining fluid to the machining area to eliminate machining chips.

Next, when measuring the machining shape of the initial machining by wire cutting, the Z-axis motor is controlled by NC control.
24 is driven to bring the measuring head 22 close to the workpiece 12, and the positioning of the measuring head is controlled by NC control so that the tip of the measuring head faces the machining groove of the workpiece 12. Then, pressurized air is jetted and supplied from the air jet nozzle 23 to discharge and remove the working liquid adhering to the working groove or the like, and the working shape is detected and measured. This shape measurement can be performed extremely accurately and at high speed by non-contact measurement by the triangulation method as described with reference to FIG. 1, and can be measured while tracing the machining groove by NC control. The measurement results obtained by the data processing of the detected values are sequentially input to the NC control device 16 so that the correction processing of the program shape is performed. If the NC controller 16 carries out the finishing process by the wire-cut electric discharge machining again after the program correction as described above, the corners and the like can be improved in precision and can be precisely finished.

It should be noted that the machining shape can be measured by detecting the previous machining state and repeating the program correction each time the second cut is repeated, or the machining locus of the machining contour can be obtained by machining a part of the programmed contour shape. Combination control of shape measurement and re-machining, such as measurement, program correction and subsequent machining, can be arbitrarily performed. Further, the reworking control based on the measurement result is not limited to the correction of the program, and the reworking condition setting control can be corrected by the measured value of the machined shape.

[0014]

As described above, according to the present invention, the reflected light when the laser beam is irradiated is detected by the optical position detector,
By providing the shape measuring device that measures the shape using the principle of triangulation, the pre-processed shape by wire cutting can be measured with high accuracy and high speed without contact.
Also, by scanning the laser spot, it is possible to easily measure arbitrary shapes, curved surface shapes, etc., and it is easy to digitize the measurement results. This measurement value can be input to the numerical controller to correct the program shape. The process can be performed very easily. Then, by performing rework finishing of the wire cut by this correction program, extremely high precision shape cutting can be performed. Further, at the time of measurement by the shape measuring device, a liquid removing device for ejecting gas from the nozzle toward the processing portion to remove the processing liquid is provided, and the processing shape is measured while removing the processing liquid, thereby performing a precise measurement and High-speed measurement can be performed very easily, and highly efficient and highly accurate wire-cut electric discharge machining can be performed.

[Brief description of drawings]

FIG. 1 is a structural diagram of a main part of an embodiment of a shape measuring apparatus provided in a wire cut electric discharge machine according to the present invention.

FIG. 2 is an overall structural diagram of an embodiment of a wire cut electric discharge machine according to the present invention.

[Explanation of symbols]

 1 Laser semiconductor 2 Reflective mirror 3 Condenser lens 4 Light receiving lens 5 Optical position detection element 6 Amplifier 7 Switch 8 Arithmetic processing unit 9 Timing pulse oscillator 10 Vibration pulse power supply 11 Vibration coil 12 Workpiece 13 Processing table 14,15 Drive motor 16 NC controller 17 Wire electrode 18 Guide 19 Machining liquid supply nozzle 20 Machining pulse power supply connection terminal 22 Measuring head 23 Air jet nozzle 24 Z axis motor

Claims (2)

[Claims] 1. A wire for performing shape cutting by electric discharge machining while performing relative movement between a wire electrode (17) and a workpiece (12) along a desired shape programmed by a numerical controller (16). In a cut electric discharge machine, a shape measuring device (1 to 11) that detects the reflected light when a laser beam is irradiated by the optical position detector (5) and uses the principle of triangulation to measure the shape is provided. The pre-machined shape according to the above is measured by the shape measuring device (1 to 11), the measured value is input to the numerical control device (16), and the program shape is corrected and reworked. Wire-cut electric discharge machine. 2. A liquid removing device for ejecting a gas from a nozzle (23) toward a processing portion to remove a processing liquid in the processing portion,
The wire-cut electric discharge machining apparatus according to claim 1, wherein when the pre-machining shape by wire cutting is measured by the shape measuring apparatus, the liquid removing device is operated to eliminate the machining liquid in the machining portion. ..